Structural, impedance and electrochemical double-layer capacitor characteristics of improved number density of charge carrier electrolytes employing potato starch blend polymers

Abstract

Potato starch (PS)/graphene oxide (GO) blend–based solid polymer electrolyte has been doped with lithium trifluoromethanesulfonate (LiCF3SO3) via casting method. Lithium-based system is further infused with ionic liquid, 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]) as a plasticizer to form a PS/GO/LiCF3SO3/[Bmim][Cl] electrolyte with improved conductivity characteristic. The ionic liquid–based polymer electrolyte PS/GO/LiCF3SO3/[Bmim][Cl] exhibits better physical properties based on structural characterisation and thermal analysis conducted. Values of linear sweep voltammetry (LSV) that evaluates the electrochemical potential window for salted and plasticized systems are 1.38 V and 1.92 V, respectively. Specific capacitance (Cs) values calculated from charge–discharge measurement and cyclic voltammetry (CV) for the plasticized system are higher compared with those for the salted system. From the galvanostatic charge–discharge analysis, the value of Cs obtained for PS/GO/LiCF3SO3/[Bmim][Cl] is 37.9 F g−1 at 0.6 mA cm−2 current density. The results from CV and galvanostatic charge–discharge analysis confirm the suitability of PS/GO/LiCF3SO3 and PS/GO/LiCF3SO3/[Bmim][Cl] for electrochemical double-layer capacitor (EDLC) application.